Synthetic aperture techniques have been applied very successfully for
many years in astronomy and radar to obtain high resolution images, an outstanding
example in recent years being the use in remote sensing satellite systems.
In underwater acoustics, because of the inherent problems caused by
random fluctuations in the signal path, the slow velocity of the acoustic wave
and the unknown movements of the transducer as it traverses the aperture,
the application of the synthetic aperture technique has mainly been limited to
the very useful but rather inferior non-coherent technique known as side-scan
sonar. However the rapid advances that are being made in micro-chip technology
and fast digital signal processing, and the development in image
processing algorithms has created renewed interest in the possible application
of the synthetic aperture technique to underwater acoustics. This thesis
describes such a study.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.